Talk:Common Scrambling Algorithm

Does anyone actually know how brute-force can be improved on, or if it can be improved on? topynate 23:39, 20 Sep 2004 (UTC)

I haven't heard of anything, but it wouldn't be surprising — it certainly wouldn't be the first time that a reverse-engineered proprietary encryption algorithm had been found to be weak! — Matt 12:02, 21 Sep 2004 (UTC)

Can anybody reference where to find the information about bytes 3 and 7 being checksums or if you could explain how to calculate them. - Aldebarn42

Byte form AA BB CC xx DD EE FF yy -- xx and yy are checksums, xx=AA+BB+CC, yy=DD+EE+FF. I suspect this is in the BISS specification somewhere. So that's bytes 3 and 7 when starting count at 0. —Preceding unsigned comment added by 87.194.114.122 (talk) 00:36, 23 March 2008 (UTC)[reply]

The entry says:

This fact allows practical space-time tradeoff attack where 32 bits are brute-forced, 16 bits are calculated with memory tables built from ciphertext, and 16 bits calculated as checksum with a running time of O(216)+O(232), which can be less than a second if implemented in FPGA hardware or on scalable architecture like cell processor.

Is there any reference to this affirmations? —Preceding unsigned comment added by 85.152.200.43 (talk) 18:36, 9 July 2009 (UTC)[reply]

Check http://www.cdc.informatik.tu-darmstadt.de/~kwirt/csa.pdf Implementation in a fpga would consist of a number of parallel engines that would try to decrypt and check if the content is valid. (looking for known things like mpeg-headers etc). With 42 parallel hw-threads, that each test one key per clock-cycle, for this @ 50Mhz this would allow for a bruteforce attempt in ~1 second since on average we would expect to find the key after 2^31 tries for a 2^32 bit key.